On Jun 26, 3:50 pm, "RST Engineering" wrote:
Let's take ten watts from a battery or from the wall plug.

A light bulb (just for illustration sake, don't take the numbers as gospel)
spends 9.9 of those watts generating heat and 0.1 of the watts generating
light.

An LED spends 9 of those watts generating heat and 1 of those watts
generating light. The LED is therefore about ten times as efficient as a
light bulb.

However, the light bulb has about five or six square inches over which to
get rid of the 9.9 watts of heat (although the bulb is still very hot) while
the LED has less than a quarter of a square inch (without a heat sink) to
get rid of the 9 watts. Which one do you think will get hotter?

Jim

--
"Life is not a journey to the grave with the intention of arriving safely in
a pretty and well preserved body, but rather to skid in broadside,
thoroughly used up, totally worn out, with chocolate in one hand and wine in
the other, loudly proclaiming 'WOO HOO What a Ride!'"
--Unknown

"Jose" wrote in message

et...



And, [LED lights] are going to get hotter than
billy blue blazes unless you keep airflow over them.

Moreso than the edison invention? If so, where's the efficiency coming
from?

Jose- Hide quoted text -

- Show quoted text -

Hi Jim,

Actually, the lightbulb dissipates most of its heat as Infra-red
radiation so it dosn't get terribly hot (other than the filament).
Remember that the visible light is only the tail of the black-body
radiation spectrum emitted by the bulb, so from a pure radiation
perspective its fairly efficient, but not from a visible light
perspective.

The LEDs have to dissipate most all of their waste heat via conduction
and convection, and very little by radiation. So they have their own
thermal challenges.

But there are ways to make it work....

Dean